The EP-4643 series RAID subsystem features 6Gb SAS or 8Gb FC-AL host performance to increase system efficiency and performance. It features high capacity expansion, with 64 hot-swappable SAS2/SATA3 hard disk drive bays in a 19-inch 4U rackmount unit, scaling to a maximum storage capacity in the terabyte range. The EP-4643D series also supports dual controllers which provide better fault tolerance and higher reliability of system operation.